MIMO CDMA-based Optical SATCOMs: A New Solution

A new scheme for MIMO CDMA-based optical satellite communications (OSATCOMs) is presented. Three independent problems are described for up-link and down- link in terms of two distinguished optimization problems. At first, in up-link, Pulse-width optimization is proposed to reduce dispersions over fibers as the terrestrial part. This is performed for return-to-zero (RZ) modulation that is supposed to be used as an example in here. This is carried out by solving the first optimization problem, while minimizing the probability of overlapping for the Gaussian pulses that are used to produce RZ. Some constraints are assumed such as a threshold for the peak-to-average power ratio (PAPR). In down-link, the second and the third problems are discussed as follows, jointly as a closed-form solution. Solving the second optimization problem, an objective function is obtained, namely the MIMO CDMA-based satellite weight-matrix as a conventional adaptive beam-former. The Satellite link is stablished over flat un-correlated Nakagami-m/Suzuki fading channels as the second problem. On the other hand, the mentioned optimization problem is robustly solved as the third important problem, while considering inter-cell interferences in the multi-cell scenario. Robust solution is performed due to the partial knowledge of each cell from the others in which the link capacity is maximized. Analytical results are conducted to investigate the merit of system.Comment: IEEE PCITC 2015 (15-17 Oct, India

A new trade-off scheme for MIMO OFDM-based cognitive radio systems over correlated fading channels

A joint pre- and post-coder (JPROC) is proposed for MIMO OFDM-based cognitive radio systems over correlated fading channels. The main aim is to have a trade-off between licensed networks and un-licensed networks in the underlay scenario. To handle the un-desired interferences on the main networks, the eigen-values of this JPROC should be small in each licensed network, as much as possible, whereas un-licensed users have higher rates. Frequency selective MIMO fading channels are coded with orthogonal space-time-frequency block codes (OSTFBCs) to improve the bad effects of these small eigen-values on the signal to noise ratio (SNR) in the main network. On the other hand, the system is operated in both transmit- and receivecorrelation scenarios. We have the correlation matrices at all the transmitters imperfectly. This is because there is any error in the estimation of the transmit- and the receive- angle spreads. The matrix of the JPROC is obtained by solving a robust convex optimization problem in the multi-user scenario. The optimization problem is represented under some constraints such as the outage probability of eavesdropping as a criterion for secrecy. An upper-band of the pair-wise error probability is minimized, while controlling the produced interferences. The effective performance of this JPROC is finally shown using simulations

A Newly Secure Solution to MIMOME OFDM-Based SWIPT Frameworks: A Two-Stage Stackelberg Game for a Multi-User Strategy

The paper technically proposes a newly secure scheme for simultaneous wireless power and information transfer (SWIPT) frameworks. We take into account an orthogonal frequency division multiplexing (OFDM)-based game which is in relation to a multi-input multi-output multi-antenna Eavesdropper (MIMOME) strategy. The transceiver is generally able to witness the case imperfect channel state information (ICSI) at the transmitter side. Transferring power and information are conducted via orthogonally provided sub-carriers. We propose a two-step Stackelberg game to optimise the Utility Functions of both power and information parts. The price for the first stage (in connection with information) is the total power of the other sub-carriers over which the energy is supported. In this stage, the sum secrecy rate should be essentially maximised. The second level of the proposed Stackelberg game is in association with the energy part. In this stage, the price essentially is the total power of the other sub-carriers over which the information is transferred. In this stage, additionally, the total power transferred is fundamentally maximised. Subsequently, the optimally and near-optimally mathematical solutions are derived, for some special cases such as ICSI one. Finally, the simulations validate our scheme as well, authenticating our contribution’s tightness and efficiency

Asymptotic Bound of Secrecy Capacity for MIMOME-Based Transceivers: A Suboptimally Tractable Solution for Imperfect CSI

The paper principally proposes a suboptimally closed-form solution in terms of a general asymptotic bound of the secrecy capacity in relation to MIMOME-based transceivers. Such pivotal solution is essentially tight as well, fundamentally originating from the principle convexity. The resultant novelty, per se, is strictly necessary since the absolutely central criterion imperfect knowledge of the wiretap channel at the transmitter should also be highly regarded. Meanwhile, ellipsoidal channel uncertainty set-driven strategies are physically taken into consideration. Our proposed solution is capable of perfectly being applied for other general equilibria such as multiuser ones. In fact, this in principle addresses an entirely appropriate alternative for worst-case method-driven algorithms utilising some provable inequality-based mathematical expressions. Our framework is adequately guaranteed regarding a totally acceptable outage probability (as 1 − preciseness coefficient). The relative value is almost 10% for the estimation error values (EEVs) ⩽0.5 for 2×2-based transceivers, which is noticeably reinforced at nearly 5% for EEVs  ⩽0.9 for the case 4×4. Furthermore, our proposed scheme basically guarantees the secrecy outage probability (SOP) less than 0.05% for the case of having EEVs ⩽0.3, for the higher power regime